Surface test indicator



Aug. 4, 1953 G. c. WELCH SURFACE TEST INDICATOR Original Filed Oct. 5, 1949 III--- INVENTDRV GERALD E. WIEILEH 'l as ATTDRNEY Patented Aug. 4, 1953 SURFACE TEST INDICATOR Gerald G. Wclch, Rochester, N. Y.

Original application October 5, 1949, Serial No. 119,626. Divided and this application June 17, 1952, Serial No.293,884

3 Claims. 01. 33-172l This invention relates to surface test indicators, and more particularly to contact elements therefor.

In test indicators of the type disclosed in copending applications Serial No. 119,626, filed October 5, 1949, and Serial No. 245,054, filed September 4, 1951, now'Patent 2,621,413, granted December 16, 1952, it is desirable to provide a contact element that is adapted for internal as well as external usage, and provide an element of sufiicient size as to be able to withstand ordinary wear, as well as small enough to project into small bores. At the same time, the contact region of such element should at all times bear a given relation with respect to the pivot point of such element in the gage proper, in order that accurate indications may be had.

The present invention is a division of application Serial No. 119,626, aforesaid, and is directed to a contact element construction in which contact elements of different diameters are provided, the smaller of which, when not in use, may be protected by the larger, and in which either ele ment bears a common relation to the pivot point of the contact element.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, wherein like reference characters indicate like parts:

Figure 1 is a plan View of a test indicator having the contact element of th invention applied thereto;

Figure 2 is atop plan view of the indicator with the cover plate removed therefrom;

Figure 3 is a longitudinal section of the indicator of Figure 1, taken substantially on the line i at 5 and 6, and is held on the lower part of the housing by means of the screws or studs 1 and 8. Pivotally mounted on the stud 1 is the operating arm 9 shown in Figures 2 and 3. A bifurcated :pointer I0 is provided, which. is pivoted on the stud 8. On this pointer ID are two studs H and I2, adapted to be engaged :by projections l3 and I4 by which the pointer I0 is moved in an indicating direction upon movement of the arm 9 in either direction. The pointer 10 is normally and the other hand lllb swings below the dial plate 3.

The lower part of the housing I has an annular rim 22 with an inwardly extending flange 23 on the bottom thereof, which rim and flange serves as a seat for the crystal 24.

The cover plate 2 istriangular in shape at the left as shown in Figures 1 and 2, and, as shown in Figure 3, has an annular rim 28 to the right fitted with a crystal 29.

The operating arm 9 extends to the left of the stud 1 on which it is pivoted. Also pivoted on stud l is the contact element 36, which is recessed to receive the left hand end of the arm '9 as at 35. On the outer end of the contact element 36 is the threaded stem 31 with a male thread 3| thereon. diameter extension 32 terminating in the ball contact tip 38. The step extension and the ball contact tip are very small in diameter, and are intended to engage in very small holes, or fine Work.

On the outside of the threaded stem 31 is engaged a threaded sleeve 40 having a female thread on the inside thereof. On the end of this sleeve is a large ball contact tip 4| that is intended to engage in large bores, or upon coarse work. This large ball cont-act tip is normally in place on the small tip and protects the small tip, but when it is desired to use the small tip, the large tip can be removed, and this will expose the small tip for use.

The root diameter of the threads on stem 3'! is approximately that of the ball contact tip'38, whereby the large ball contact, with its internally threaded sleeve 40 may freely pass over the tip 38 and be threaded in place, with its end 43 in The stem has a reduced abuttin relation to the shoulder 44, The axial distance from the shoulder 44 to the center of the small ball tip is preferably substantially the same as the distance from the abutment 43 to the center of the tip 4 I, so that indications of the gage will be approximately the same, regardless of the tip employed.

The arm frictionaily gripped between the bifurcatedend 35' of the element 36, whereby the element may be angularly disposed in various positions with relation to the arm 9, the friction,

however, being sufiicient to transmit-movement of the element to the arm 9, to actuate the indicator.

Although a single embodimentoithe invention has been illustrated and describe*d,..itisto.;be:

understood that the invention is not limited thereto. As various changes in the construction and arrangement may bemade without'depart ing from the spirit of the invention, as will be apparent to those skilled in the art, reference Willbe had'to the appended claims fora definition'of the limits of the invention.

What is claimed is:

1. In a ball tip for 'adialindicator, acontact 2. In a contact member for a dial indicator, a frame, a bifurcated member pivoted in said frame, an indicating arm having an end frictionally and pivotally positioned within said hifurcated end, a threaded shank formed on said member, terminating in a reduced diameter stem portion and contact ball of a diameter not greaterthan the root'diamet'er of the threads'of said threaded shank, and an internally threaded sleeve adapted to be threaded on said shank and having acavity to receive said contact ball, said sleeve havingrat its outer end a second contact ball, and means providing a limit for limiting the extent said sleeve may be threaded upon said shank, saidlimit being adapted to center said second contact ball concentrically with the first-named contact ball.

3. In a ball tip for a dial indicator, a contact tip comprising a member having a shank adapted to receive a protecting sleeve, said shank having a simulder at one end for engaging an end of said sleeve when positioned over said shank for establishing an end position of the sleeve with respect to the shank, a reduced diameter stem projecting from the other end of said shank terminating in a bali of a diameter less than-any shank cross-sectional dimension, said sleeve at its other end terminating in a hollow ball tip adapted to be substantially concentrically located with respect to the first-named ball when said sleeve is in protecting position and. in the said end position with respect to said shank, and means for frictionally securing saidsleeve on said shank;

GERALD C. WELCH.

No references cited. 

